1. Field of the Invention
The present invention relates to an exposure method and device, and particularly to an exposure method and device which effects exposure by light emitting elements such as LED chips or laser diode (LD).
2. Description of the Related Art
Conventionally, in an image recording apparatus such as a printer, in which an image is exposed onto a photosensitive material based on image data and an image recorded by the exposure on the photosensitive material is transferred to a plain paper and is outputted, an exposure device is used in which light emitting elements such as LED chips or LD, which are used for exposure of the photosensitive material, are provided in a light source portion.
In such conventional image recording apparatus, in order to allow high-speed recording of an image on a photosensitive material, a plurality of light emitting elements are provided in a light source portion along a sub-scan direction and a plurality of scanning lines are simultaneously formed in the sub-scan direction at one main scan operation, thereby allowing recording of an image.
In the above-described conventional image recording apparatus having a plurality of light emitting elements, it is necessary that the plurality of light emitting elements be mounted correctly to predetermined positions along a sub-scan direction of the light source portion so that exposure positions of the plurality of light emitting elements on the photosensitive material, which are provided along the sub-scan direction, are arranged on the same straight line along the sub-scan direction. However, these light emitting elements are not necessarily mounted to correct positions due to positional errors of mounted light emitting elements in a production process of the light source portion or due to displacement of the mounted positions of the light emitting elements caused by environmental variation after the production, or the like.
When the plurality of light emitting elements are not mounted to correct positions in the light source portion, these light emitting elements cannot be caused to emit light so that exposure positions of the light emitting elements on the photosensitive material are arranged on the same straight line along the sub-scan direction. As a result, there exists a drawback in that the quality of an image obtained finally deteriorates.